Isabelle Renimel

Reverse Pharmacognosy: Application of Selnergy, a New Tool for Lead Discovery. The Example of ε-Viniferin

The aim of reverse pharmacognosy is to find new biological targets for natural compounds by virtual or real screening and identify natural resources that contain the active molecules. To demonstrate the applicability of this concept, we report here a study on eviniferin, an active ingredient for cosmetic development. Nevertheless, this natural substance is weakly defined in terms of biological properties. SELNERGY, an inverse docking computer software, was used to identify putative binding biological targets for eviniferin. Among the 400 screened proteins two targets were retained. For cosmetic application, cyclic nucleotide phosphodiesterase 4 (PDE4) was the most interesting candidate. Moreover, other PDE subtypes (1, 2, 3, 5 and 6) were not retained, indicating a selectivity for PDE4. The experimental binding tests on the 6 subtypes of PDE revealed a significant selectivity of eviniferin for the PDE4 subtype. This selectivity was confirmed by evaluation of eviniferin on the secretion of TNF-α and Interleukin-8. Our data demonstrated that eviniferin possesses anti-inflammatory properties by inhibiting PDE4 subtype. In conclusion, reverse pharmacognosy and its inverse docking component cannot only be integrated into a program for new lead discovery but is also a useful approach to find new applications for identified compounds.

Bioactive molecules in Kalanchoe pinnata leaves: extraction, purification, and identification.

Kalanchoe pinnata (Lam.) Pers. (syn. Bryophyllum pinnatum; family Crassulaceae) is a popular plant used in traditional medicine in many temperate regions of the world and particularly in South America. In Guyana, the leaves are traditionally used as an anti-inflammatory and antiseptic to treat coughs, ulcers, and sores. The purpose of this study was to implement a method for targeting and identifying molecules with antimicrobial activity, which could replace chemical preservatives in cosmetic applications. The leaves were extracted by a method based on pressurized liquid extraction (PLE), using different solvents. A study of antimicrobial activity and cytotoxicity tests were performed to select the most interesting extract. To isolate one or more active molecules, the selected crude extract was fractionated by centrifugal partition chromatography (CPC) and then antimicrobial activity and cytotoxicity of each fraction were tested under the same procedure. The last step consisted of identifying the main compounds in the most active fraction by LC-MS/MS.

Production of melanin bleaching enzyme of fungal origin and its application in cosmetics

We screened wild fungal isolates for melanolytic activity and found thatSporotrichum pruinosum was the most promising of the very limited number of fungi that decolourised synthetic melanin. We used a submerged aerobic process to produce a skin depigmentation enzyme by this strain, and found that in the medium the presence of Mn2+ ions was necessary, the limitation of carbon source was beneficial, and Zn2+ ions were inhibitory. Cultivation in a stirred bioreactor required immobilization of mycelium and use of low stirring velocity. A partially purified enzyme was prepared and tested for depigmentation of human skin corneocytes and whole epidermis of phototypes III and V. This is the first study demonstrating the effective enzymatic degradation of the skin melanin rather than inhibition of its synthesis. This opens the possibility of using melanolytic enzymes in cosmetic skin lightening.

Pentacyclic triterpenes from Manilkara bidentata resin. Isolation, identification and biological properties.

Three pentacyclic triterpenes were isolated for the first time from resinous plant Manilkara bidentata. Ultrasound-assisted extraction with ethanol was chosen after a comparison of various extraction methods. Analysis of the extract was performed by HPLC with evaporative light scattering detection and semi-preparative HPLC has enabled us to isolate two urs-12-enes (3β-O-acetyl-α-amyrin and 3β-O-trans cinnamyl-α-amyrin) and a lupane-type derivative (3β-O-trans cinnamyl lupeol). Structures were elucidated on the basis of HRESIMS, atmospheric pressure photoionization MS, and homo- and heteronuclear correlation NMR experiments. Antioxidant and anti-inflammatory activities were determined on Manilkara extract and isolated fractions. We have also investigated their action on collagen and fibronectin synthesis, two very important proteins of the extracellular matrix. Thus, Manilkara extract was able to decrease IL-1β and IL-8 pro-inflammatory cytokines. These activities exhibit the potential use of Manilkara extract as an anti-inflammatory and anti-aging ingredient for pharmaceutical and cosmetic industries.

Synthesis, Purification, and Activity of Salidroside

Abstract Our goal was to synthesise this compound by glucosylation of p‐tyrosol. The 74% yield of the reaction was not satisfactory and instead of optimising the procedure, we preferred to purify the product. This was achieved by high performance centrifugal partition chromatography with an optimised biphasic system followed by a solid phase extraction on a graphitic stationary phase. The final product was found to be pure at 95%. The structure of salidroside was confirmed by both NMR and ESIMS2. Each 13C NMR, 1H NMR, and ESIMS2 signals were attributed to the salidroside structure. The last step of this work was to assess the biological activity of the synthetic salidroside. It was found to be more biologically active than ginsenoside Rb1 on the ATP production rate of keratinocytes.